Staten Island Advance/Bill LyonsDiane Kowalewski pleaded guilty last week in Stapleton Criminal Court to a felony count of third-degree grand larceny, stemming from the sale of this home at 198 Cranford Ave.

STATEN ISLAND, N.Y. -- She’s 70, and she could be spending up to nine months in jail.

Diane Kowalewski must also repay $160,000 to her former brother-in-law after admitting she cheated him on the sale of her late ex-husband’s New Dorp home, prosecutors said.

Ms. Kowalewski pleaded guilty last week in Stapleton Criminal Court to a felony count of third-degree grand larceny, stemming from the sale of the home at 198 Cranford Ave.

The residence belonged to Lawrence Kowalewski, who died more than four years ago, said prosecutors.

Kowalewski’s brother, Philip Kowalewski, had expected to inherit some of the estate.

However, not long after Kowalewski died, Ms. Kowa-lewski, who was the administrator of her former husband’s estate, showed up in New York City Surrogate’s Court with her boyfriend and a will. It stated that she would inherit everything, a law enforcement source said.

The will seemed suspect, the source said, so the court hammered out a deal.

She could sell the house in New Dorp, and Philip Kowalewski would get $160,000 from the sale, according to court papers. Ms. Kowalewski could keep whatever was left after all costs were paid.

Except that when she sold the home — for $400,000, the source said — she took off with the money, leaving the brother with nothing, authorities allege.

That led to a probe by District Attorney Daniel Donovan’s NYPD detective squad, and investigators tracked her to Omaha, Neb., in February of last year. She was arrested and voluntarily returned to Staten Island.

Under the terms of her plea, Ms. Kowalewski’s sentence will be capped at nine months, according to Donovan’s spokesman. She must also pay restitution to Philip Kowalewski.

Prosecutors will recommend nine months, the spokesman said, but the judge could sentence Ms. Kowalewski to a lesser jail term or probation.

Sentencing is set for April 19. Assistant District Attorney Jeffrey Curiale is prosecuting the case.